WESTFORD, Mass., May 5, 2009 – Sonus Networks, Inc. (Nasdaq: SONS), providing network transformation through IP communications technology, today announced results for the first quarter ended March 31, 2009.

Revenue for the first quarter of fiscal 2009 was $41.0 million, compared to revenue from continuing operations of $89.5 million in the fourth quarter of fiscal 2008 and $73.6 million for the first quarter of fiscal 2008. The Company’s net loss on a GAAP basis was $16.2 million, or $0.06 per share, for the first quarter of 2009, compared to a loss from continuing operations of $99.0 million, or $0.37 per share, for the fourth quarter of 2008, and income from continuing operations of $1.0 million, or $0.00 per share, for the first quarter of 2008. The Company ended the quarter with cash, cash equivalents, marketable securities and investments totaling $386.1 million.

"The economic environment continues to be challenging," said Richard Nottenburg, president and chief executive officer of Sonus Networks. "We took additional cost and realignment actions during the first quarter and continued to focus our investment dollars on delivering new products and services which enhance the value proposition we bring to customers. The strength of our balance sheet - specifically substantial cash and investments with no debt, gives us confidence we have the resources we need to achieve our plan."

Conference Call Details

Sonus Networks will host a conference call for analysts and investors to discuss its first quarter 2009 results today at 10:00 a.m. ET.

To listen via telephone:

Dial–in number: 800–908–8951 International Callers: +1 212–231–2902

To listen via the Internet

Sonus will host a live webcast of the conference call. To access the webcast, visit www.sonusnet.com, About Us, Investor Relations.

About Sonus Networks

Sonus Networks, Inc., providing network transformation through IP communications technology, is leading the evolution of communications networks to support the multi-media, multi-device demands of today's digital lifestyle. Sonus solutions and services enable fixed, mobile and cable operators to gain network awareness and new multi-media capabilities essential to retaining and expanding their subscriber base. Through standards-based interoperable solutions and services, Sonus extends the investments made in traditional networks by enabling operators to seamlessly migrate to next generation technology and deliver the secure, reliable, scalable and cost-effective network needed to grow their business. For more information visit www.sonusnet.com.

This release may contain forward-looking statements regarding future events that involve risks and uncertainties. Readers are cautioned that these forward-looking statements are only predictions and may differ materially from actual future events or results. For a discussion of the risks and uncertainties which could cause actual results to differ from those contained in the forward-looking statements, see "Risk Factors" in our Annual Report on Form 10-K for the fiscal year ended December 31, 2008 and Quarterly Report on Form 10-Q for the quarter ended March 31, 2009. Risk factors include among others: the unpredictability of our quarterly financial results; risks and uncertainties associated with the Company's previous restatement of its historical stock option granting practices and accounting including regulatory actions; actions that may be taken by significant shareholders; risks associated with our international expansion; and the impact the current global financial market conditions may have on the telecommunications industry. Any forward-looking statements represent Sonus' views only as of today and should not be relied upon as representing Sonus' views as of any subsequent date. While Sonus may elect to update forward-looking statements at some point, Sonus specifically disclaims any obligation to do so, except as required by law.

Sonus is a registered trademark of Sonus Networks, Inc. All other company and product names may be trademarks of the respective companies with which they are associated.

For more information, please contact:

Sonus Investor Relations:
David Roy / Karin Cellupica
978–614–8615
droy@sonusnet.com
kcellupica@sonusnet.com

Media Relations:
Lucy Millington
1–978-614-8240
lmillington@sonusnet.com